The Phase I program will extend existing computer software and use it to analyze dose-response data obtained from bacterial interactions with selected antimicrobial agents. The Spiral Plating Method will be used to provide - from a single petri-dish - data on bacterial population changes and colony size variation over a range of up to 600: 1 in antimicrobial agent potency. Existing laser scanning instrumentation will transfer plate measurements into memory of developmental computer hardware for automated analysis of the dose-response data. Applicability of automated dose-response analysis derived from a single petri-dish will be evaluated for antimicrobial and genetic damage assays. Significantly more and better information is anticipted for these and similar bacterial interaction processes, with subtantial reduction in the cost - in time and materials - of these assays. Antimicrobial applications include validation of drug potency, antibiotic levels in body fluids and susceptibility, particularly for drug combinations. Genetic damage applications are exemplified by the automated analysis of dose-response data containing both mutagenic (revertant) as well as toxic regions. The Phase II program will develop detailed test methodologies and validate them in collaborative studies. Automated dose-response analysis wil broaden the Spiral System microbiology product line and substantially extend the range of its applications. This will provide access to a much larger, world-wide market for its instruments and services in microbiological testing.